I bought it 25 years ago. The current ones seem to be branded Irwin Record, not plain Record. Still selling much the same range of vices, with this workshop vice at the bottom end made of close grained grey iron, and engineers vices made of S. G. Ductile iron selling for 10 times as much...
I'll try with my massive adjustable spanner (if I've not got a conventional spanner that fits) and a lump hammer, after a good soaking in PlusGas. And buy a new vice I guess?